explain_rule

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description discloses what the tool returns (description, spec reference, severity, triggers, fix) which adds context beyond the readOnly and idempotent annotations. It clarifies that it explains how to fix issues rather than applying fixes, consistent with the read-only hint. No contradiction with annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two sentences with no waste. The first sentence states the purpose and enumerates return content; the second provides usage context and its role relative to validate_vast. It is front-loaded and efficient.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a single-parameter read-only tool with an output schema, the description is complete. It specifies what it does, how to obtain valid rule IDs, and its role in the validation workflow. Nothing an agent needs to call it correctly is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema description coverage is 100% and already includes an example and instruction to use list_rules for valid IDs. The description repeats 'Use rule IDs from list_rules' but adds little beyond the schema. With full schema coverage, the description provides marginal additional value, so baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses the verb 'Get' and specifies the resource 'full details for a specific VAST validation rule', enumerating the exact details returned (description, spec reference, severity, triggers, fix). It also distinguishes itself from siblings by calling itself 'the primary tool for understanding and fixing VAST issues flagged by validate_vast', making its purpose unambiguous.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It provides clear usage context by instructing to 'Use rule IDs from list_rules' and states it is the primary tool for understanding/fixing issues from validate_vast. It does not explicitly contrast with alternatives like inspect_vast or fix_vast, but the guidance is sufficient for an agent to know when to use it.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.